1. Field of the Invention
The present invention relates to a copyrighted-work distribution-and-receiving system in which data is generated from the contents of copyrighted work and distributed through a given transmission path, and a receiving fee is imposed on a receiving side in units of received contents; a copyright management apparatus used in such a system for performing management of copyright related to copyrighted work; and a copyrighted-work distribution apparatus having a copyright management function.
2. Description of the Related Art
Digital satellite broadcasting has become widespread. Compared with analog broadcasting, digital satellite broadcasting is immune to noise and fading, and allows high-quality signal transmission. In addition, the bandwidth efficiency has been improved and multiple channels can be used. In digital satellite broadcasting, for example, one satellite can provide several hundred channels. In such digital satellite broadcasting, a number of special channels have been provided, such as a sport channel, a movie channel, a music channel, and a news channel. In these special channels, programs having corresponding special contents are broadcasted.
Among these special channels, a music channel is popular in which promotion programs, such as those introducing new songs and hit songs, are mainly broadcasted.
As described above, programs for new-song introduction and hit songs are transmitted with a moving picture and sound in a conventional music channel. When an audience finds a favorite musical piece in the music channel, the audience may consider buying a CD of the musical piece being introduced. Alternatively, the audience may want to obtain information on an artist playing the musical piece and information of an album including the musical piece. It would be very convenient if, while the audience is viewing a music program, the audience could obtain information on the artist and the album including the musical piece, or if the audience could download the audio data of a musical piece which they like. Since the moving picture and the sound of a musical piece are transmitted only one way in the conventional music channel, such a demand cannot be satisfied.
To solve this drawback, a musical-contents distribution system has been proposed (Japanese patent application No. Hei-9-308488) in which information related to music broadcasted in a music channel can be easily obtained, and musical-piece data can be easily downloaded to a data storage apparatus.
A so-called FLAT accounting method for a music broadcasting channel is known. In this method, when the user pays a flat monthly charge, the user can watch a plurality of music broadcasting channels.
In the above accounting method, however, if a flat monthly change is paid, all broadcasted musical pieces can be recorded into a digital recording medium such as a Mini Disc (MD) any number of times. If this case occurs, since a distribution business party cannot determine which musical piece is recorded by the audience, the party cannot pay an appropriate copyright fee to the copyright holder of the musical piece, which is copyrighted work. Therefore, copyright may be insufficiently protected.
Such a problem occurs not only in a system that distributes musical contents but also in a video-contents distribution system and further in a system that widely distributes copyrighted work, such as a character-and-image-information distribution system like a so-called electronic library.